This invention relates generally to a weapon training simulator and more particularly to apparatus for sensing the intersection point of a line with a target plane along with associated shot sound simulation systems.
There are many applications where it is necessary or desirable to accurately sense the intersection point of a line and a plane substantially perpendicular to that line. Among such applications are weapon aiming and firing simulators, machinery or tool alignment devices, measuring instruments and surveying instruments. In each of these applications it is essential that the line-plane intersection point be accurately determined. Early systems were primarily optical in nature and involved a human observer sighting through an optical system employing cross hairs or other indicia who specified when the indicia was aligned with a determinable target in the target plane. While such systems have and do suffice for many applications, for many other applications it is desirable to have the alignment system automatic preferably without the normal errors associated with human intervention in the use of optics. Because of the desire for automatic systems and the relatively large number of applications, there have been a number of systems devised to accomplish this.
Among the prior art automatic line-plane intersection determining devices is that of J. Thorn in U.S. Pat. No. 3,739,176 issued June 12. 1973. Thorn3 s device incorporates plural sensing means to detect relative movement from a predetermined relationship with a laser beam. Each sensing means has two pairs of photoelectric sensors with one pair determining relative movement vertically and the other pair, horizontal movement. Another prior art device is disclosed by N. F. Clayborne in U.S. Pat. No. 3,012,469 issued Dec. 12, 1961, wherein a beam of light does not reach either of two photoelectric sensors when centered between them but does reach one or the other if displaced from the centered position. Yet another prior art device is disclosed by K. Martin in U.S. Pat. No. 3,617,759, issued Nov. 2, 1971. In the Martin device, when a light beam is centered on a four element cross shaped sensor array, comprised of two pairs of sensors, there is no output from the associated electronic system and displacement of the beam from center results in a differential output from one or the other or both pairs to correspond to the displacement.